It is a startling coincidence to have, in one season, the appearance of not one but two memoirs about William Shawn, the former editor of the New Yorker Ved Mehta's Remembering Mr. Shawn's New Yorker: The Invisible Art of Editing and Lillian Ross's Here but Not Here: A Love Story (Random House, $22.50, 0375501193) but perhaps more interesting is that, while each is an elegy for Shawn, the two...